Various techniques are known in the art for transforming a section of an optical fiber into an optical modulator while keeping the fiber itself intact. For example, U.S. Patent Application Publication 2008/0166120 describes a modulator arrangement for acoustically modulating optical radiation. The modulator arrangement has a waveguide portion formed from a flexible material, a vibrator element for generating acoustic vibrations, and a coupling arrangement for releasably coupling the vibrating element to the waveguide portion. The coupling arrangement include a first coupling member secured to the waveguide portion, and a second coupling member secured to the vibrator element.